Function cpp20_and_in_constexpr

Source/external/fast_float.h:267–273

namespace fast_float {

fastfloat_really_inline constexpr bool cpp20_and_in_constexpr() {
#if FASTFLOAT_HAS_IS_CONSTANT_EVALUATED
  return std::is_constant_evaluated();
#else
  return false;
#endif
}

// Compares two ASCII strings in a case insensitive manner.
inline FASTFLOAT_CONSTEXPR14 bool